1. Field
Apparatuses and methods consistent with the exemplary embodiments relate to video management for a surveillance system, and more particularly, to video management for a surveillance system, which can improve recording performance of the surveillance system and reduce input/output (I/O) loads through separately implementing elements for storage only and elements for reproduction, backup, and overwrite.
2. Description of the Related Art
Recently, video surveillance systems using surveillance cameras, such as closed-circuit television (CCTV), have been rapidly spread. In such surveillance systems, data from the surveillance cameras is stored in real time in one physical hard disk drive or logical hard disk drive through a network. Further, recorded video can be confirmed using a client program, and the recorded video data can be backed up and stored in another storage medium.
FIG. 1A is a conceptual view explaining a storage operation of a surveillance system in the related art, FIG. 1B is a conceptual view explaining a backup operation of the surveillance system in the related art, and FIG. 1C is a conceptual view explaining a reproduction operation of the surveillance system in the related art.
In FIG. 1A, a surveillance system 1 in the related art registers a recording schedule for storing surveillance video data that is acquired by cameras 2. Further, the surveillance system 1 designates a hard disk 3 in which the acquired video data is to be stored. Then, the video data is stored in a file in the hard disk 3, which is designated by the user, in the order of time. Thereafter, if the designated hard disk is fully filled with the data, the oldest data in the hard disk 3 is searched for and deleted to store latest data instead.
In FIG. 1B, in the case where a user has set a backup start time and a backup end time, the video data file in the hard disk 3 is searched for and is converted into another format, and the surveillance data is stored in another storage medium 4, e.g., a digital versatile disk (DVD), an external hard disk, a universal serial bus (USB), a network drive, or the like. Here, the hard disk 3 is the same single hard disk.
In FIG. 1C, the data stored in the past can be confirmed through searching for, sending to a client, and reproducing the surveillance data stored in the hard disk 3 that is designated by the user. Here, the hard disk 3 is the same single hard disk.
According to the surveillance system 1 in the related art, however, one physical hard disk 3 serves to perform storage, reproduction, and backup of the data, and even if a plurality of physical hard disks 3 are provided, only one logical hard disk performs the storage, backup, and reproduction of the data.
The best write performance of a physical hard disk drive may be related to the size of a buffer of a memory. The video data that is received through a network is written as a file in the hard disk after being first stored in the buffer of the memory through a Network Interface Card (NIC), and at this time, the processing speed differs for about one second. That is, due to the low capacity that is the disadvantage of the memory and the low processing speed that is the disadvantage of the hard disk, the memory is unable to store a large amount of data, and the hard disk is unable to rapidly bring the data from the memory. At an initial stage, a plurality of hard disks are installed to overcome the disadvantage. The write speed at which one hard disk can theoretically process data may correspond to 100 MB, but in this case, it is required for the data to be sequentially input in the unit of 4 K without a read operation.
However, in the surveillance system, in which video data is received through a network, the data that comes through the network has a delay, and thus, it is unable to successively receive the data.
The write speed may be increased through using a plurality of hard disks. However, if many built-in hard disks are installed, many bus lines are connected to the hard disks, and thus, data is divided to be sent to the hark disks through the bus lines, rather than being simultaneously sent. This may cause reduction of the speed by 1/N.
In addition to the write of the video data, reproduction, backup, and overwrite of the video data are required. For example, while the latest video data is written, the past video data should be searched for to be sent to a client, or the oldest data should be searched for to be deleted to secure the hard disk capacity. Since an actuator of one hard disk searches for the data to perform reproduction, backup, and overwrite of the data, the write speed is lowered, and the hard disk is worn away to reduce the lifespan thereof.
Further, if the hard disk is unable to bring the video data that is stored in the memory, memory overflow occurs and the video data is lost. Accordingly, in order to store the video data at high picture quality that is set by a user without a video loss even in the case where the reproduction and the backup simultaneously occur, it is required for the video data to be stored in one physical hard disk at a write speed of up to 125 Mbps.
According to the surveillance system 1 in the related art, however, in the case where many surveillance cameras are connected to one surveillance system to reproduce videos which are simultaneously stored and to perform backup for long-term preservation of the surveillance data, the data from the surveillance cameras is stored in real time in one physical hard disk drive or one logical hard disk drive through a network, and thus, the performance of the surveillance system deteriorates due to the processing speed of the hard disk, reduction of the write speed caused by the reproduction and backup, and insufficient memory capacity.